Configure apache. (The apache configuration file is located at /etc/httpd/conf/httpd.conf and explicitly include /etc/http/conf.d/*.conf). Copy the example config file to that location:
cp /opt/graphite/examples/example-graphite-vhost.conf graphite.conf /etc/httpd/conf.d/graphite.conf

service httpd start (not started by default. Need to set it for auto start)

/etc/init.d/httpd reload (not necessary but for clarity with the graphite install instructions and to make sure the config file works.)